1. Field of the Invention
The present invention relates to a revolving structure in glasses where, relative to a first member, for example, a bracket, a second member, for example, a temple, is revolved with resistance.
More specifically, the present invention relates to a revolving structure for a glasses part where, when a glasses part is revolved, a proper resistance force (a grip feeling) is generated, and movement of the glasses part is restricted after the revolution, so that positional deviation of the glasses part is not caused.
2. Description of the Related Art
Conventionally, as a revolving structure for a glasses part, a structure such as shown in FIGS. 9(a-b) and 10 has been known (for example, see Patent Literature 1).
In FIGS. 9(a-b) and 10, for attaching a main front frame 100 to a sub-front frame 101 in a revolvable manner thereto, a revolving structure for the glasses part is applied to a bridge portion 102.
FIG. 9(a) shows a state that the main front frame 100 is suspended from the sub-front frame 101.
FIG. 9(b) shows a state that the main front frame 100 has been revolved relative to the sub-front frame 101.
FIG. 10 shows a revolving structure for the main front frame 100.
A rotational shaft 103 with a round-bar shape is used for a coupling structure of the main front frame 100 and the sub-front frame 101.
The rotational shaft 103 and a resin-made pipe 105 shown in FIG. 10 are revolved according to the revolution of the rims 104 of the main front frame 100.
At that time, the rotational shaft 103 and the resin-made pipe 105 are revolved integrally against a frictional resistance with a bridge casing 106 and a resilient force of a leaf spring 106a. 
That is, the resin-made pipe 105 contacts with the wire-like leaf spring 106a and the bridge casing 106, while the rotational shaft 103 and the resin-made pipe 105 contact with each other via a whole circumferential face of the rotational shaft 103, so that the rotational shaft 103 and the resin-made pipe 105 are rotated integrally with each other.
When a user stops the revolution of the main front frame 100 at his/her desired angle, the resin-made pipe 105 and the rotational shaft 103 are held at the stopped position owing to the frictional resistance between the resin-made pipe 105 and the bridge casing 106 and the biasing force due to the resilient deformation from the leaf spring 106a. 
Detent feeling occurs according to the revolution of the main front frame 100 to the sub-front frame 101.
Patent Literature 1: JP-A-2003-121803
In the revolving structure for a glasses part described above, however, since a contacting area between the resin-made pipe 105 and the bridge casing 106 is small, even if the leaf spring 106a is pressed by a screw 107, a sufficient frictional resistance cannot be obtained.
That is, since the resin-made pipe 105 only contacts with a recessed face of the bridge casing 106 at three portions thereof and with the leaf spring 106a at one portion thereof in a linear manner, frictional force cannot be developed sufficiently.
On the other hand, in such a revolving structure, a space occurs necessarily between the recessed portion of the bridge casing 106 and the resin-made pipe 105 and dust or the like easily enters in the space, so that frictional damage may be caused due to the dust biting in the resin-made pipe 105.